3 Commits (e3941109af1d8203dddc2aa12e33170d6dca5c4b)

Author	SHA1	Message	Date
Paul Mackerras	ec2fa61792	execute1: Reduce width of the result mux to help timing ... This reduces the number of different things that are assigned to the result variable. - The computations for the popcnt, prty, cmpb and exts instruction families are moved into the logical unit. - The result of mfspr from the slow SPRs is computed in 'spr_val' before being assigned to 'result'. - Writes to LR as a result of a blr or bclr instruction are done through the exc_write path to writeback. This eases timing considerably. Signed-off-by: Paul Mackerras <paulus@ozlabs.org>	4 years ago
Paul Mackerras	0c714f1be6	execute: Move popcnt and prty instructions into the logical unit ... This implements logic in the logical entity to calculate the results of the popcnt* and prty* instructions. We now have one insn_type_t value for the 3 popcnt variants and one for the two prty variants, using the length field of the decode_rom_t to distinguish between them. The implementations in logical.vhdl using recursive algorithms rather than the simple functions in ppc_fx_insns.vhdl. This gives a saving of about 140 slice LUTs on the A7-100 and improves timing slightly. Signed-off-by: Paul Mackerras <paulus@ozlabs.org>	5 years ago
Anton Blanchard	b8fb721b81	Consolidate logical instructions ... Consolidate and/andc/nand, or/orc/nor and xor/eqv, using a common invert on the input and output. This saves us about 200 LUTs. Signed-off-by: Anton Blanchard <anton@linux.ibm.com>	5 years ago